People often place feeders in their backyards to attract hummingbirds, songbirds, and other flying animals (e.g., bats, moths, butterflies) to identify them, observe them in close proximity, and experience their presence when outdoors. These highly desirable animals most often migrate with the seasons and as such, are typically thought of as summer flyers but some species of birds (e.g., chickadee, sparrow) commonly overwinter in the higher latitudes where winter climates can include freezing temperatures and snowfall. During periods of snow and freezing temperatures, the seeds, nuts, and insects upon which overwintering birds rely may become covered by snow or ice and drinking water sources may freeze over—leaving them with diminished availability of sustenance essential to their very survival. Of those who put out seed and water sustenance for flying animals, many neglect to check and refill their feeders and even those that do so regularly may find it burdensome or impossible to keep dry food accessible in the presence of snow, and maintain a constant supply of liquid water during freezing temperatures.
Though most hummingbird species are migratory, the Anna's hummingbird can be found year-round along the Pacific coast as far north as British Columbia, Canada. Additionally, members of migrating hummingbird species may arrive early in the season to claim territory for attracting a mate, or stay late—being caught off guard by an early season storm. Younger birds may find themselves trapped in winter areas due to their inexperience with migration and hummingbirds of any age may be victims of storms or other factors that push them off course into winter's path. When temperatures drop, hummingbirds are vulnerable to the scarce supply of insects and nectar that are so vital to their survival.
Backyard feeders can be life-savers for hummingbirds that find themselves in winter climates but the nectar (sugar water) in the feeders may freeze—depriving hummingbirds of a food source on which they rely. Though bird enthusiasts (birders) may take measures to keep nectar within their feeders from freezing (e.g., bringing them in at night, increasing sugar content, using elaborate lamps or heat tape), they may miss the fact that a feeder is empty or the nectar within frozen, and one day without this food supply may spell doom for the bird that is living in sub-freezing temperatures. Some birders may keep two feeders and exchange the freezing one with a warm one that has been kept indoors—sometimes several times a day, but this scheme is difficult to maintain for those at work or on vacation. During the summer months, flying animal enthusiasts may not be aware when high temperatures have spoiled the liquid sustenance within their feeders—possibly driving birds away from their feeders or even making them ill.